Presently there exist numerous types of anti-skid systems combined with brake control apparatus for achieving effective and reliable braking action on a moving vehicle. The aircraft industry requires such systems so as to achieve optimum braking action upon an aircraft during its braking procedure on the runway. Heretofore, such systems have been mechanical or hydraulic in nature requiring a mechanical or hydraulic linkage between the braking pedals and the metering valves. Being of hydraulic-mechanical nature, such systems have been bulky in construction, susceptible to failure of mechanical parts, and inherently messy due to hydraulic leakage. Further, presently available systems utilize two separate and distinct valves, one being the metering valve and the other an anti-skid valve to control braking. Such construction is inherently expensive due to the presence of two valves and further adds to the potentials for failure.
Consequently, it is an object of the invention to present an anti-skid system and brake control device whereby much of the trouble with mechanical linkage and hydraulic interconnections of presently utilized systems may be alleviated.
Still another object of the invention is to present an anit-skid system and brake control device wherein a single valve per brake may be utilized for both braking and anti-skid purposes.
Yet another object of the invention is to present an anti-skid system and brake control device wherein anti-skid signals and brake pedal signals may be combined and applied to a valve driver for exciting a single valve.
Still a further object of the invention is to present an anti-skid system and brake control device which is reliable in operation, relatively inexpensive to construct and maintain, and readily adaptable for implementation with state of the art elements.
These objects and other objects which will become apparent as the detailed description proceeds are achieved by an anti-skid system and brake control device for use on a vehicle having at least two wheels and having anti-skid circuitry connected to said wheels for providing anti-skid signals indicative of skidding activity and further having brake pedal transducers for producing pedal signals indicative of the degree of brake pedal depression, comprising: rectifiers connected to the transducers for producing a D. C. level from the associated pedal signals; differencing circuits connected to the rectifiers and anti-skid circuits and producing brake signals indicative of the difference between the pedal and anti-skid signals; brake valve means connected to each of said wheels; and valve driving means interconnected between said differencing circuit and said brake valve for regulating the application and release of brake pressure according to said brake signals.